HELP with calibrating...

1) with some of the slippier strings, the string slips right through the string gripper, and I can never get a stable tension. What should I do?

2) When I tension a string and clamp it, then I untension it, the clamp recedes a little bit. Is that ok?

3)the tension was off by 5 pounds when pulled at 50, so i followed the instructions, took off the string gripper, took off the cover on the electronic tensioner, put the string gripper back on. I pull at 50 again, and it's dead on precise, which is weird, because according to the instruction booklet i was supposed to fool around with some screws to get the right tension.
Anyways, I put the cover back on, put the gripper back on again, pull at 50 and for some reason it's off by 5 pounds AGAIN!!

There is probably an adjustment for increasing the pressure on the string being pulled. It should be explained in the owner's manual. When the gripper needs cleaning, this can also allow the string to slip.

When the clamp moves a little that's called drawback. I think most all machines have a little drawback.

If the gripper is working right, I think I would make a five pound adjustment and put it back together and see how it reads.

Well, I did the calibration with a rougher string that didn't slip, so I'm sure the calibration was acurate. Thanks for the suggestion, I'll try making the adjustment.

As for the string gripper, I can't see a pressure adjustment screw or anything of that sort anywhere, and it's not in the manual either, but I found out that if I put the string through the gripper then keep it at angle, it doesn't slip at all, so I'll just do that for now I guess.